1. Field of the Invention
The present invention relates to the generation of profiles for the rotors of a screw compressor, and more particularly to the generation of profiles for the female rotor and the male rotor of a screw compressor which give an optimum relation between the two rotors and thereby increase the working efficiency of the screw compressor and reduce the mechanical loss thereof.
2. Description of the Prior Art
Generally speaking, a screw compressor is provided with a male rotor and a female rotor which intermesh with each other when they rotate. These screw rotors are asymmetrical in their contour and usually have considerably complicate profiles. To improve the working performance of such compressor and the techniques used to produce such compressor, various kinds of problems are faced by the designers. For example, to improve the working efficiency of the rotors, it is necessary to take into account of the rotors, the dimensions and clearance tolerance of housing in which the rotors work, the length of sealing line, and the area of the blow hole.
It is a common way for the conventional screw compressor to reduce the area of the blow hole to increase the working efficiency thereof. However, the area of the blow hole is not the only factor which has influence on the working efficiency and the production technique of the screw compressor. First, the length of the sealing line affects the working efficiency, too. By the sealing line, it means the contact line between the rotors. When the sealing line is too long, the clearance between the rotors increases and thereby reduces the working efficiency of the compressor. Secondly, when the blow hole is too large, fluid in the compressor will leak from the high-pressure chamber into the low-pressure chamber therein and thereby reduces the working efficiency, too. In addition, the profile of rotors also largely affects the working efficiency of the compressor.
As to the technique used to produce the compressor rotors, better quality toothed cutters, higher accuracy achieved at lower cost, and prolonged cutter life, all are necessary conditions to be considered.
In view that the profile of rotors has great influence on the efficiency of the screw compressor, it is therefore tried by the inventor to develop a new method to generate the profiles that give the rotors of the compressor the optimum working efficiency.